The ear canal 10, as illustrated in FIG. 9, is generally narrow and tortuous and is approximately 26 millimeters (mm) long from the canal aperture 11 to the tympanic membrane. The lateral part 12 is referred to as the cartilaginous canal due to the underlying cartilaginous tissue. The medial part, proximal to the tympanic membrane, is rigid and referred to as the bony region 13 due to the underlying bone tissue. The dimensions and contours of the ear canal vary significantly among individuals. There is a characteristic “S” shape with a first and second bends generally occurring at the aperture area 11 and junction area 8, respectively.
Canal dimensions vary significantly along the ear canal and among individuals.
Placement of a canal hearing device inside the ear canal 10 and concha region 5 can be challenging due to difficulty in access and manipulation of a miniature canal device, particularly when placed deeply inside the ear canal. However, it is generally desirable to place a hearing device deep inside the ear canal for achieving various advantages including reduction of the acoustic occlusion effect, improved energy efficiency, reduced distortion, reduced receiver (speaker) vibrations, and improved high frequency response. A well-known advantage of deep ear canal placement is aesthetics as many hearing-impaired individuals refuse to wear visible hearing devices such as in-the-ear (ITE) or behind-the-ear (BTE) types.